simpleCudaGraphs fails with illegal memory access + weird invalid parameter setting

[eyalroz]

In the simpleCudaGraphs example, in function cudaGraphsManual, we have:

cuda::graph::node::parameters_t<node_kind_t::kernel_launch>* params_ptr = nullptr;
cuda::graph::instance::set_node_parameters<node_kind_t::kernel_launch>(instance, reduce_final_node, *params_ptr);

that should not have been there... :-(

Also, graph execution is currently failing in cudaGraphsManual() is failing on the first run with "an illegal memory access was encountered".